This chapter is from the book

This chapter is from the book

This
chapter
covers
the
following
Cisco-specified
objectives
for
the "Technology" section
of the
CCNA
exam:

Compare
and
contrast
key
characteristics
of
LAN
environments

Describe
network
communications
using
layered
models

Describe
the
components
of
network
devices

This
chapter
also
covers
the
following
Cisco-specified
objective
for
the "Planning
and
Designing" section
of the
CCNA
exam:

Design
a
simple
LAN
using
Cisco
technology

A
network device may utilize various
components to achieve connectivity
and increase functionality. These
components are fundamental to
internetworking.

This
chapter specifically focuses on
the Data Link layer of the OSI
model and how network communications
occur at this layer.

LAN
environments at the Data Link
layer may be set up with token
ring, Fiber Distributed Data Interface
(FDDI), or one of many ethernet
data-link protocols.

Various
network designs or layouts commonly
are used to set up a LAN. At the
Data Link layer, LANs may be connected
with either a bridge or a switch.
The operation of these devices
is described in Chapter 8, "Bridging
and Switching Operations."

Outline

Introduction

Data
Link Protocols

Token
Ring

FDDI

Ethernet
at the Data Link Layer

Ethernet
Addressing

Ethernet
Framing

Physical
Ethernet Standards

Ethernet

Fast
Ethernet

Gigabit
Ethernet

10-Gigabit
Ethernet (10GbE)

Long
Reach Ethernet

Data
Link Layer Devices

Bridges

Switches

Duplex

Microsegmentation

Chapter
Summary

Apply
Your Knowledge

Study
Strategies

Read
the objectives at the beginning
of the chapter.

Familiarize
yourself with token ring and FDDI
protocols.

Define
the IEEE MAC unicast, broadcast,
and multicast addresses.

Review
the ethernet family of protocols
and be able to identify the characteristics
of each protocol.

Name
the devices that are used at the
Data Link layer and important
traits of each device.

Define duplex.

Describe
microsegmentation.

Introduction

Several data link networking concepts were first introduced in the discussion
of the Data Link layer or Layer 2 of the OSI model in Chapter 1, "Standard
Internetworking Models." Again, it is important to understand the layered
architecture of the OSI model to grasp the fundamentals of how a network
operates. Although Chapter 2, "Physical Layer Networking Concepts," went
over concepts that define the Physical layer of the OSI model, this chapter goes
over concepts that define how a network operates at the Data Link layer
specifically.

Important Data Link LAN topics to understand for the CCNA exam include the
protocols, addressing, and devices that are used at Layer 2. Cisco specified
several objectives related to LAN technologies, which are prevalent at Layer 1
and Layer 2. Let’s begin with three Data Link layer protocols: token ring,
FDDI, and ethernet.

NOTE

Remember that the Physical and Data Link layers are combined in the TCP/IP
model to form the Network Interface layer.